Abstract: In recent years, copper-based perovskite has attracted widespread attention in the field of light emission and scintillation due to its excellent stability and environmental friendliness. However, most researches were focused on the 0D and 1D CsCu₂I₃ crystals, which limit the understanding for the intrinsic properties and anisotropy, as well as the practical application in scintillators. In this paper, a high-quality CsCu₂I₃ crystal with length of 5 mm was successfully grown by the solution cooling method. The crystal presents a transparent colorless appearance, with distinct edges and exposed facets. XRD results indicate that the CsCu₂I₃ crystal maintains good stability even after 6 months. The absorption spectrum shows an absorption peak of CsCu₂I₃ crystal at 310 nm. The band gap width is calculated to be 3.42 eV, indicating that the CsCu₂I₃ crystal is a wide-bandgap semiconductor. The emission wavelength of CsCu₂I₃ crystal is located at 580 nm, with full width at half maximum (FWHM) of 75 nm. The luminous chromaticity of the CsCu₂I₃ crystal falls at coordinates (0.47, 0.50) in the yellow region on the CIE chromaticity diagram, belonging to a warm white tone with color temperature of 3 000 K. It is consistent with its yellow emission of the CsCu₂I₃ crystal under the ultraviolet lamp. The fluorescence lifetime of the CsCu₂I₃ crystal is measured to be 51.6 and 215.5 ns.

Key words: CsCu₂I₃, crystal growth, solution method, bulk single crystal, optical property